Universal serial bus (USB) has evolved from a data interface capable of supplying limited power to a primary provider of power with a data interface. Today, many devices charge or get their power from USB ports contained in laptops, cars, aircraft, or even wall sockets. USB has become a ubiquitous power socket for many small devices such as cell phones, MP3 players and other hand-held devices. USB may fulfill user requirements of data transfer, but may also to provide the ability to power or charge devices without the need to load a driver on the devices.
Over time, power requirements of USB devices have increased. One result of the increase in power requirements is an increase in charge time for devices which utilize USB ports to charge batteries.